http://www.transitofvenus.nl/history.html
Historical observations of the transit of Venus, from Steven van Roode.
Thorough overview of places where the transit of Venus has been observed in the past and which I could identify using Google Earth. The stations are listed by sponsoring country and nationality, following the longitudinal position from west to east. Many entries have links to primary sources.

http://www.phys.uu.nl/~vgent/venus/venustransitbib.htm
Extensive bibliography of original sources relating to transits of Venus, with links to many of the original publications; from R.H. van Gent. 

http://eclipse-maps.com/Eclipse-Maps/Transits.html
Historical transit of Venus maps by Michael Zeiler, with emphasis on Richard Proctor's maps.

http://image.gsfc.nasa.gov/poetry/venus/VT8.html
NASA's Sten Odenwald notes some possible sightings of the transit of Venus prior to Jeremiah Horrocks, including by Assyrian, Chinese, and Aztec sky watchers.

http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1882MNRAS..43...41J
On the Probable Assyrian Transit of Venus by Rev. S.J. Johnson (1882) suggests an Assyrian tablet may refer to an ancient recorded transit, as mentioned in a previous journal.

http://www.nojum.net/articles/venustransit/history/
Pouria Nazemi asserts in Nojum, The Astronomy Magazine of Iran that the Persian Islamic scientist Avicenna witnessed the 1032 transit of Venus.  Avicenna claims in his book Shifa, "I say that I have seen Venus as a spot on the Sun’s face."

http://transits.mhs.ox.ac.uk/
A browseable database of historical instruments and images from collections around the world; from the Scientific Instrument Commission (SIC) of the International Union of the History and Philosophy of Science.  Institutions and individuals are invited to develop the site by contributing their own material.